It is commonplace for publicly accessible facilities to provide soap dispensers in washrooms and other areas. Some systems are designed to receive disposable refill units produced in a sanitary environment. When empty of product, the whole reservoir is replaced along with the accompanying nozzle and pump. In this way, every part wetted by soap is disposed of when the dispenser is serviced. This greatly reduces and/or eliminates the germination of bio-films and contributes to the cleanliness of the facility.
In many instances, soap dispensers are automated to provide hands-free operation. These types of dispensers eliminate direct contact by the user, thereby reducing the possibility of germ transmission. Sensors are typically installed at a location near the nozzle where fluid product is discharged. When a user positions his or her hands near the sensor, the fluid dispenser automatically dispenses a measured amount of fluid product. A motor drives the pump which is fluidly connected to the reservoir. Naturally, power is needed to drive the motor which in some instances is supplied by a direct connection to the facilities main power. However, it is significantly easier to install a dispenser that has a self-contained source of energy.
For dispensers using an onboard power supply, electrical energy is often supplied in the form of batteries installed into the dispenser housing. However, one problem with dispensers of this type relates to the maintenance and replacement of the batteries. It is difficult or impossible to tell how much power is remaining in the batteries of a dispenser, or how spurts in usage will drain the remaining power in the batteries. To prevent dispenser downtime, service personnel must repeatedly check the batteries or replace the batteries before they are fully discharged, neither of which is cost-effective.
To alleviate this problem, it is possible to incorporate additional batteries into the refill unit. In this way a fresh supply of batteries is provided every time the dispenser reservoir is replaced. Moreover, the size and power output capacity of batteries in the dispenser can be scaled down and sized to accommodate the duty cycle of a single dispenser refill. The refill unit batteries can be provided in the form of “coin cells”, also known as watch batteries, which are small and relatively inexpensive. However, coin cells are incapable of rapidly discharging energy. If power is drawn too quickly from a coin cell, the useful life of the battery can be greatly reduced.
To maximize the useful life of a coin cell battery, some dispensers incorporate an energy storage device, like for example a capacitor, to provide power to the dispenser motor. The capacitor is capable of supplying quick bursts of energy to the motor. After one or more dispensing cycles, the capacitor may be slowly recharged by the coin cell. However, capacitors have limited storage capacity and drain quickly with repeated use. In busy environments, the capacitor may be incapable in keeping up with dispensing activity. Accordingly, the controller must then draw power from the onboard batteries. In environments with less traffic, energy stored in the capacitors may dissipate over time. Even though the capacitor may be recharged from the onboard batteries, energy is being used but fluid product is not being dispensed. In this instance, the batteries may be depleted long before the reservoir is empty of product.
What is needed is a way of dynamically drawing energy from the onboard power supply that corresponds to the frequency of usage of the fluid product dispenser. The embodiments of the subject invention obviate the aforementioned problems.